Substituted pteridines and method of preparing the same



Patented Dec. 4, 1951 UNITED STATES FATENT OFFICE 2,577,039 SUBSTITUTEDPTERIDINES ND METHOD or PREPARING THE SAME Barbara Roth, MiddlcsexBorough, N. J assignor to American Cyanamid Qompany, New York, N. Y., a corporation of Maine Nb brewing. Application June 11, 1949, Serial No. 98,638

'10 Claims. (01. zen- 2ers) This invention relates to new organic compounds and to methods of preparing the same. More particularly, it relates to substituted pteridines and their preparation.

The structure and synthesis of pteroylglutamic acid, commonly called folic acid, was first disclosed by Angier et al.; Science 103; 667 (1946). This compound has been found to be valuable in the treatment of certain diseases of the circulat'ory system and in nutrition.

In the co-lpen'ding application of Doris R. Seeger Serial Number 781,495, filed on October 2 2,- 1947, now Patent No. 2,568,597, there is disclosed and claimed a number of substituted pteridines, among these being the 4-amin'o analog of pteroylglutamic acid which can be illustrated by the follow'ing'structural formula:

The '-amino derivatives of amino acid amides 6i. pteroic acid, particularly 4-aminopteroylglutamic acid, have been found highly active in the treatment of neoplastic diseases in man and animals. The compound, 4-amiho'pteroy1glu t'air'ii'c acid, has been used in the treatment of leukemia and tumors of various kinds in man and animals. However, this compound is highly to The therapeutic dosage of these amino compounds is often very close to the level at which toxic manifestations appear. The margin of safety in using these compounds is therefore rather narrow and less toxic compounds would be more desirable.

fhav'e now found that the substitution of other groups for one or both of the hydrogen atoms of the a-amin'o group results in a marked decrease in toxicity. The resulting 4-substituted amino d ri atives or the amino acid amides of pteroic' acid have been found to havean extremely low toxicit and in fact some of the derivatives a pear to be weak growth promoters of .Streptococ cusfde'cdZi s'R one of the organisms customarily uses in the assay of pteroylglu'tamic acid and its derivatives. a

The compounds which I have found tc'be much less toxic than the -aihiflo' analogues Of pt'eroyb glutamic acid and related com ounes may be represented by the following structural formula:

WWI/ y 2 wherein R. is a monoc-yclic aryl radical, is a -=*-NH2; -NHR; -NRR; radical, R is a'---NH2; NHR; -NRl'-t' or OH radical. At least one of the groups R and R is NHR or NR3 wherein R and R are alkyl, aralkyl, aryl or radicals forming a portion of a saturated heterocyclic ring and Y is hydrogen or a lower alkyl radical.

The following table shows the relative antagonist activities of some of the 4-amino and 4-substituted amino derivatives of pteroylglutamic acid. In this table the half maximum inhibition of the growth of S. jaecalz's R. is used as a meas ure of toxicity. Table Product Activity eax'nmbpteroylglutamie 'a'cid.- N -Methylpteroylglutamic acid 4-Mthylaminopteroylglutamic acid 700% antagonist. antagonist. 2% antagonist.

4-Dimethylaminoptcroylglutamic acid 4 (l'-Piperidyl)pteroylglutamic acid-...

1% growth, vs. pteroylglutamic acid as 100%. 1.5% growth, vs. ptei oyl glutamic acid as-100%.

The compounds of the present invention can be prepared by reacting a 4,5 diaminopyrimidine, a halogeno aliphatic aldehyde or ketone and a primary aromatic amine or secondary alkyl aromatic amine under conditions which will be described hereinafter. The reaction may be made to take place by simultaneously mixing the three intermediates together, preferably in the presence of water which serves as a solvent for the intermediates and/or the reaction product. Suitable solvents for the reaction also include ethyl alcohol,- acetone, benzene, carbon tetrachloride, chloroform, acetic acid and other organic solvents and mixtures thereof with each other or with water. Some reaction may take place, however, by merely mixing the necessary reactants together and heating the mixture.

The reaetion may be represented by the following equation in which R R Y and R are as defined above, X is hydrogen or halogen and Hal is halogenz The reaction may take place over a wide range of temperatures of from about C. up to about 100 C. or even higher. Likewise the reaction will take place over a wide range of pH conditions, best results being obtained on the acid side at a pH within the range of about 1.5 to 6.

The 4,5-diaminopyrimidines in the present reaction are in most cases new compounds and a brief description will be given of their preparation. They may be added to the reaction mixture as a free base or in the form of one of their salts. Compounds such as 2,4,5-triamino-6- dialkylaminopyrimidine can be prepared by treating 2,4-diamino-6-hydroxypyrimidine with phosphorus oxychloride to obtain 2,4-diamino-6- chloropyrimidine. This chloropyrimidine is then reacted with a dialkylamine to obtain 2,4-diamino-6-dialkylaminopyrimidine, On nitrosation with nitrous acid, a 2,4-diamino-5-nitrosofi-dialkylaminopyrimi-dine is obtained which can then be reduced to the desired 2,4,5-triamino-6- dialkylaminopyrimidine. Should a 2-dialkylamino-4,5,6-triaminopyrimidine be desired as an intermediate, it can be prepared by reacting a dialkylguanidine with malononitrile to obtain a 2 dialkylamino 4,6 diaminopyrimidine. This compound, upon nitrosation and reduction, will give the desired 2-dia1kylamino-4,5,6-triaminopyrimidine. Intermediates such as 2-dialkylamino-4,5-diamino-6-hydroxypyrimidine can be prepared by the process immediately above by substituting cyanoacetic ester for the malononitrile in the reaction.

The aromatic aldehyde or ketone can be compounds such as 2,3dibromopropionaldehyde; 2,3-dichloropropionaldehyde; 1,1,3-tribromoac6- tone; 1,1,3-trich1oroacetone; butylchloral, and the like.

The primary'and secondary aromatic amines which may be used include ortho, meta and paraaminobenzoic acid and the salts, ester and amides thereof. Compounds found most useful in applicants process are the amides of paraaminobenzoic acid in which the amide-forming group is an amino acid. Particularly important intermediates include para-aminobenzoylglutamic acid and para-alkylaminobenzoylglutamic acid and polypeptides thereof such as para-aminobenzoylglutamylglutamic acid; para-aminobenzoyldiglutamylglutamic acid and others having a plurality of peptide linkages made up of one or more of the various amino acids such as paraaminobenzoylserylglutamic acid. Compounds prepared with these intermediates have a wide range of biological activity and are the preferred products of the present invention. or course, amides of para-aminobenzoic acid and other amino acids such as glycine, aspartic acid, leucine, serine, sarcosine, phenylalanine, alanine, isovaline, cystine, and the like are also important intermediates of the present invention. The amino acids may be natural or synthetic and may be in any of the d, l or d1 forms. The free carboxyl groups of these amides may be esterified, neutralized or converted into an amide without interfering with the essential reaction. In fact, in some cases it appears desirable to block off the free carboxyl group by such procedure before carrying out the reaction.

Other amides of aminobenzoic acid may also be employed in the process. Such include paraaminobenzamide and other amides formed by the reaction of aminobenzoic acid and aliphatic and aromatic amines such as ethylamine; ethanolamine; dodecylamine; ethylhexylamine; benzylhowever, the resulting product has two less hydrogen atoms than expected, the product having a fused aromatic pyrimidopyrazyl nucleus. The oxidation of the non-aromatic dihydro pyrimidopyrazyl nucleus to the aromatic form occurs by some obscure mechanism such as internal oxidation or disproportionation in that the aromatic form is obtained even under nitrogen. Better results are obtained in the process, however, when oxidizing agents are added to the reaction mixture. Suitable oxidation agents are those having an oxidation-reduction potential of about -0.49 to 1.42 volts. Among these may be mentioned iodine, potassium bromate, chlorine, benzoquinone, manganese dioxide, sodium dichromate, ferric chloride, and still others. The use of some of these is illustrated in the specific examples.

The process and representative compounds of the invention will now be disclosed in detail in the following examples. It will be understood, of course, that other products using intermediates mentioned hereinbefore may be prepared by the same process, the only essential difference being in the selection of the particular 4,5-diamino-' pyrimidine and primary or secondary aromatic amine employed. All parts are by weight unless otherwise indicated.

Example 1 A mixture of 100 g. of 2,4-diamino-6-chloropyrimidine and 200 g. of dimethylamine in 1 liter of absolute ethanol is heated in a steel autoclave at 170 C. for three hours. On cooling the resultant solution, a heavy crystalline precipitate forms, which is filtered off and dried. This weighs 102 g. and upon recrystallization from ethanol melts between l53-1'73 C. This material is very soluble in water, contains halogen, and gives off dimethylamine when an excess of 7 sodium hydroxide is added. Indications are that it is a double compound of 2,4-diamino-6-dimethylaminopyrimidine with dimethylamine hydrochloride. The substance is dissolved in water and a large excess of sodium hydroxide added, resulting in the formation of a white precipitate, which is filtered off after cooling to 15 C. After two recrystallizations from ethanol the 2,4 diamino 6 dimethylaminopyrimidine melts at l93194.5 C.

Ninety-five grams of ZA-diamino-S-dimethylaminopyrimidine dimethylamino hydrochloride complex is converted to the free base as above. The wet cake is dissolved in 500 ml. of water, and an equivalent amount of 5 N sulfuric acid added. The pH is then adjusted to 4. The mixture is heated to C. and a 30% sodium nitritesolution added dropwise, until a permanent spot on starch-potassium iodide paper is reached. A shiny dark red precipitate forms which is filtered off after cooling to room temperature, washed with water, and air dried. The 2,4-diamino-5- nitroso-6-dimethy1aminopyrimidine weighs 67.2

g., representing a 91% yield of product melting with decomposition at 258-259 C.

To 67 g. of 2,4-diamino-5-nitroso-6dimethylaminopyrimidine in 500 ml. of water is added a 7 solution of 5 N hydrochloric acid until all is dissolved. The solution is heated to 50 C., and g. of sodium dithionite slowly added. The resultant yellow solution is acidified to pH 2 with 1- (by olume) sulfuric "acid-and cooled to 5C. for three hours; resulting inthe formation or a heavy white precipitate. Thisis filtered off. Washed with ice Water and dried at 45 C. The yield of 2,4,5-triamino-6-dimethy1aminopyrimidine sulfate is 95.7 g., or 98% of the theoretical. Purification is accomplished by reprecipit'ati'on from alkaline solution.

A mixture of 180 g. (0.677 mole) of 2',4,5--tri amino-6-dimethylaminopyrimidine sulfate. 90 g. (0.338 mole) of para aminobenzoylglutamic acid, and. 3 liters of water is heated to 45 C. and adjusted to pH 3. To this is added dropwise and simultaneously, a solution of 33.7 g. (0.113 mole) of sodium dichromate' in 400 ml. of. water anda solution of 146 g. of 2,3-dibromopropionaldehyde in 139; g. of glacial acetic acid. The pH is maintained at 3 with 5 N sodium hydroxide. The mixture is: heated at 45 C. at pH 3 for twenty minutes longer, adjusted to pH 3.8, and cooled to 6 C. Approximately 180 g. of a lden brown product is obtained which. by chemical assay contains 37 g. of 4-dimethylaminopteroylglutamic acid, corresponding to a 23% yield based on paraaminobenzoylglutamic acid. Purification is accomplished by the following procedure. The crude product is added to 12 liters ofwater at and 325 ml. or 5 N sodium hydroxide added to effect solution. This is; allowed to stir for ten minutes, and 45 g. of calcium chloride in 110 ml. of water added. The mixture is filtered with the help of diatomaceous earth and theprecipitate washed well with hot water. To the filtrate at 60 C. is added a solution of zinc chloride to pI-I 10.8. It is then. filtered again with diatomaceous earth and the: filtrate neutralized to pH 4 with hydrochloric acid, cooled to 3 C. for an hour, and then filtered with diatomaceous earth. The cake is'then slurried in 6700 ml. of water at room temperature and. 68 g. of lime added. The mixture is. stirred at room temperature for ten minutes and then heated to 60 C., filtered and washed "with hot water. To the filtrate at 60 C. is added 10% zinc chloride solution to pH 10.8, and. the mixture then filtered with diatomaceous' earth. The filtrate is heated to 80 C. and neutralized to pI-Iv 3.6, followed by filtration of the hot solution from some tarry material. It is then cooled to 6 C. and filtered after two hours with the aid of diatomaceous earth. The precipitate: is slurried in 3400 ml. of water and warmed slowly to 60 C. while adding magnesium oxide slowly to a very faint spot on phenolphtl'ralein.paper;v After ten minutes, 5g. of activatedcharcoalis added- The mixture is stirred at 60 C. for fifteen minutes longer, and. then filtered. The filtrate is neutralized to pH 3.8 at 80 C. and filtered hot. The filtrate is cooled to 6 C., filtered, and washed with water and acetone. Afte'rdrying at 45 C., the yellow product weighs 9.2 g. and had a chemical assay of 6936 as4 dimethylaminopteroylglutamic acid. A portibn' of this material is given a second treatment with magnesium oxide-activated charcoal as above. It is then dissolved in dimethylformamide, in which it is quite Somme; given an activated charcoal treatment, and reprecipitated the addition of an equal amount of ethanol. This procedure is repeated twice more, and the product then treated once more with magnesium oxide-activated charcoal as above. The product 4' inet hyl'aminopteroylglutamic acid, is obtained as. afbri'ght yellow microcrystalline solid which. iiiel'ts with decomposition at 237239 C. (immersed at v 180 Ca).

6 Example 2 To a solution of 2.66 g. (0.01 mole) of 2,4,5- triamino-6-dimethylaminopyrimidine sulfate and 1.33 g. (0.005 mole) of para-aminobenzoylglutamic acid in 70 ml. of water at C. and pH 3 is added dropwise a solution of 2.8 g. (0.01 mole) of WW1 chloral in 3 ml. of glacial acetic acid over a twenty minute period. The pH is maintained at 3 with 5 N sodium hydroxide. The mixture is heated at 45 C. for-one hour longer, adjusted to pH 4, and cooled to 5 C. The product after dry ing weighs 2.1 g. The chemical assay is 9.5% as 4 dimethylamino il-methylpteroylglutamic acid.

Example 3 To a solution of 61.4 g. (0.23 mole) of 2,4,5,- triamino-6-dimethylaminopyrimidine sulfate and 42 g. (.13 mole) of para-methylaminobenzoylglutamic acid disodium salt in 1620 ml. of water. which has been adjusted to pH 3 and heated to 45 C., are added dropwise a solution of 49.7 g. (0.23 mole) of 2,3dibromopropionaldehyde in ml. of glacial acetic acid and a solution of 11.3 g. (0.038 mole) of sodium dichromate in ml. of Water over a 20 minute period. The pH is maintained at 3 during this period by the addition of 5 N sodium hydroxide. Heating at 45 C. is con-. tinued for thirty minutes longer, the pH then adjusted to 4.0 and the mixture cooled to 5 C. The product is then filtered off, washed with water and acetone and dried at 45 C. The golden tan 4-dimethylaminc-I T -methylpteroylglutamic acid weighs 44.7 g. The product is purified by dissolving in 3300 ml. of water heated to C. Dilute sodium hydroxide is added to obtain solution,-

which re-cguires approximately 71 ml. of 5 N- so= dium hydroxide. After fifteen minutes, 9.9 g. of calcium chloride in 25 ml. of Water is added and the mixture filtered'with the aid of diatomaceous earth. 441.0% zinc chloride solution is addedgto the filtrate to about pH 10.8 and the solution is again filtered. It is then neutralized to pH 4 at 80 (3., cooled to 5 C., and filtered with diatornaeeous earth. The cake is slurried'in 2500 ml. of Water at 80 C dissolved with dilute sodium hydroxide and carbon dioxide gas bubbled in to pH 7 While slowly cooling the mixture to 20 C. It is then filtered with the aidoi' diatomaceous earth and cooled to 5 C.. The product is filtered off and: taken up in 2- liters of water at 80 6., adding approximately 5 g. of magnesium. oxide to dissolve; After fifteen minutes, 5 g. of activated charcoal is added. The mixture is filtered after another fifteen minutes at 80 C., neutral ized. to pH 4, and cooled to 5 C. The bright ye1- low precipitate is filtered ofi, washed with water and acetone and dried at 50 0. Approximately 8.5 g. of 4-dimethy1amino-N -methylpteroylglutamic acid is obtained.

Example A reaction is carried out in a manner identical with that used in Example 2 for the 4-dimethylamino-9-methylpteroylglutamic acid except that 1.62 g. (0.005 mole) of para-methylaminobenzoylglutamic acid disodium salt is used in place of the para-arninobenzoylglutarnic acid. The brow-n 4 dimethylamino-9,10-dimethylpteroylglutamic acid which is obtained weighs 1.3 g.

Example 5' To a mixture of 2.66 g. (0.01 mole) of 2,4,5- triamino -d-dimethylaminopyrimidine sulfate and 0.69 g. (0.005 mole) of para-aminobenzoic acid at .75 5 grand PR3 is adde a ut n of @31 mole) of butyl chloral in 3 ml. of glacial acetic acid over a twenty minute period. The pH is maintained at 3 with sodium hydroxide. The mixture is heated for 30 minutes longer at 45 0., adjusted to pH 4, cooled, and the 4-dimethylamino-Q-methylpteroic acid is filtered off; weight, 2.2 g.

Example 6 Example 7 This reaction is carried out in a manner analogous to Example 4 using butyl chloral and paramethylaminobenzoic acid. A yield of 1.6 g. of 4-dimethylamino9,10-dimethylpteroic acid is obtained.

Example 8 2,4,5-triamino-6-dimethylaminopyrimidine sulfate is reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylaspartic acid in the same fashion as described in Example 1 to produce 4- dimethylaminopteroylaspartic acid.

Example 9 2,4,5-triamino-6-dimethylaminopyrimidine sulfate is reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylglutamylglutamylglutamic acid in the same fashion as described in Example 1 to produce 4-dimethylaminopteroylglutamylglutamylglutamic acid.

Example 10 2,4,5-triamino-6-dimethylaminopyrimidine sulfate is reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylserylglutamic acid in the same fashion as described in Example 1 to produce 4-dimethylaminopteroylserylglutamic acid.

Example 11 A mixture of 12 g. (0.083 mole) of 2,4-diaminofi-chloropyrimidine and 15.5 g. (0.5 mole) of methylamine in 100 ml. of absolute ethanol is heated in an autoclave at 120 C. for three hours. The "resultant solution, which is a dark yellow with a blue fiuoresence, is filtered from a small amount of insoluble material and vacuum distilled'to remove the ethanol. is dissolved in 60 ml. of warm water and filtered from a small dark precipitate. The mixture is cooled and 50% sodium hydroxide added until an oil separates. It is then extracted with isopropyl acetate. On cooling the ester extracts, a yellow solid, 2,4-diamino-6-methylaminopy rimidine, crystallizes; dry weight, 3.4 g. This is recrystallized twice from ethanol and then melts at 192-194 C.

Upon nitros-ating 2,4-diamino-S-methylaminopyrimidine by the same procedure as described in Example 1, a shiny cherry-red product, 2,4- diamino -nitroso-G-methylaminopyrimidine, is obtained which after reprecipitation from acid solution melts with decomposition at 245-247 C.

2,4 diamino-5-nitroso-6-methylaminopyrimidine is reduced with sodium dithionite in a manner similar to that described in Example 1.

2,4,5 triamino-6-methylaminopyrimidine sulfate is condensed with para-aminobenzoylglutamic acid and 2,3-dibromopropionaldehyde in The residual oil the same fashion as the above described reaction with the G-dimethylamino derivative, except that barium chloride is added to the reaction mixture to convert the pyrimidine sulfate to the more soluble hydrochloride. From a reaction using 2.7 g. of 2,4,5-triamino-6-methylaminopyrimidine sulfate, 7.2 g. of product is obtained having a chemical assay of 10% as 4-methylaminopteroylglutamic acid.

Example 12 Four hundred grams of 2,4-diamino-6-chloropyrimidine is mixed with 1200 ml. of piperidine and slowly heated over a one hour period to C. on the steam bath. After an additional two and one-half hours at 100 C., 300 ml. of ethanol is added to the hot mixture, which is then filtered from piperidine hydrochloride. The solvents are distilled from the filtrate under reduced pressure, whereupon the residue crystallizes. After extracting from water-soluble impurities, 330 g. or 62% of the theoretical yield of 2,4-diaminofi-(l-piperidyl) pyrimidine is obtained. Upon recrystallization from naphtha, silvery white plates, melting at -136.5 C., are obtained.

The nitrosation of 2,4-diamino-6-(l-piperidyl) pyrimidine is carried out in the same fashion as that used in Example 1. A bright red nitroso derivative is formed, which melts with decomposition at 2ll.5-213.0 C.

The reduction of 2,4-diamino-5-nitroso-6-(1- piperidyl) pyrimidine is carried out in the same manner as previously described.

The condensation of 2,4,5-triamino-6-(l-piperidyDpyrimidine sulfate with para-aminobenzoylglutamic acid and 2,3-dibromopropionaldehyde is carried out in the same fashion as that described in Example 1. In a run using 230 g. of 2,4,5-triamino-6- l-piperidyl) pyrimidine sulfate, 260 g. of golden brown product is obtained, which gives a chemical assay indicating the presence of 44 g. of 4-(l-piperidyl) pteroylglutamic acid having the following formula:

This is purified by methods analogous to those previously described for the 4-dimethylaminopteroylglutamic acid.

Example 13 A mixture of 50 g. of dicyandiamide and 100 g. of dimethylamine hydrochloride is heated to C. for three hours and then poured into 600 ml. of absolute ethanol. The solution is cooled to 10 C. and filtered from a small amount of white precipitate. To the filtrate is then added 58.5 g. of sodium methylate. The mixture is heated to refluxing, and 66.7 g. of malononitrile is added dropwise over a twenty minute period. Refluxing is contained for two hours, after which the mixture is cooled and the product is filtered off and washed with ice water to remove salt. Approximately 61 g. of 2-dimethylamino-4,6-diaminopyrimidine, a white product, is obtained, which after recrystallization from dilute alcohol melts at 259260 C. v

To a slurry of 10 g. of 2-dimethylamino-4,6-

diaminopyrimidine in 200 ml.- of water is added an-equivalent amount of N sulfuric acid, and sodium acetate to adjust the pH to about 4. The solution is heated to '85" C. and a% solution of sodium nitrite added slowly until a permanent spot on starch-potassium iodide paper is reached. A red-precipitate is formed, which is filtered oil? after cooling. Dry weight, 11.2 of Z-dimethylamino-4,6 diamino 5-nitroscpyrimidine; melting point 283 C. (decomposition).

To 42.9 g. of 2-dimethylamino-4,6-diamino-5- nitrosopyrimidine in 550 ml. of water isadded 5N hydrochloric acid to pH 2.5. Sodium dithionite is then added slowly at approximately C. until all of the red color of the mixture is gone. Approximately 130 g. is required. The mixture is heated to C. to complete the reaction and then acidified to approximately pH 2 with dilute sulfuric acid. The product precipitatesas the sulfate, and is filtered oif after cooling well; dry weight, 56 g. It is purified for analysis by reprecipitation from alkaline solution.

A mixture of 21.3 g. of 2-dimethylamino-4,5,6- triaminopyrimidine sulfate (prepared above) and 19.5 g. of barium chloride dihydrate in 330 m1. of water is heated to 60 C. for ten minutes, cooled to 45 C. and 10.7 g. of para-aminobenzoylglutamic acid added. The pH is adjusted to 3, and solutions of 3.98 g. of sodium dichromate in 23 ml. of water and 17.6 g. of 2,3-dibromopropionaldehyde in 16 ml. of glacial acetic acid are added dropwise over a twenty minute period, maintaining the pH at 3 with sodium hydroxide. Heating at 45 C. is continued for 20 minutes longer, after which the mixture is cooled and the product filtered off, washed with water and acetone, and dried. This weights 40.6 g. and cont'ains 5.73 g. of N KN -'dimethyl 4 amino pteroylglutamic acid by chemical assay. This compound has the following formula:

it purified as follows: 38 g. of the crude product is slurried in 1600 m1. of water, heated to C., I

and 37 m1. of 5 N sodium hydroxide added. After all is in solution, 5.1 g. of calcium chloride in 13.2 ml. of solution is added, and the mixture filtered with the aid of diatomaceous earth. The filtrate is acidified to pH 10.8 with 10% zinc chloride solution, clarified, and neutralized to pH 3.8 with hydrochloric acid. After cooling well, the precipitate is filtered off and slurried in 820 ml. of water with 7.4 g. of lime. This is heated to 80 C. for fifteen minutes, filtered with diatomaceous earth and the filtrate treated with 10 Zinc chloride to a pH of 10.8. The mixture is again clarified and neutralized to pH 3.8, followed by cooling well and filtering off the product. This is then taken up in 650 ml. of water, heated to 80 C. and 0.7 g. magnesium oxide added. After treating this mixture with. 1 g. of activated charcoal, it is clarified, neutralized to pH 4, cooled well, and the precipitate filtered off. This is then recrystallized twice from 0.1 N hydrochloric acid, followed by another magnesium oxide-activated charcoal treatment as. above described. There is-then obtained 1.4 g. of a yellow microcrystalline solid having a chemical assay of 79.9% as N ,N -dimethyl i-aminopteroylglutamic acid.

ill

Example 14 To a mixture of 5.32 g. of 2-dimetnylam1no- 3,5,G-triaminopyrimidine sulfate and 4.88 g. of barium chloride dihydrate in ml. of water which has been heated for ten minutes at 60 C. is added 2.66 g. of para-aminobenzoylglutamicacid. The pH is adjusted to 3, and a solution of 5.6 g. of butyl chloral in 6 ml. of glacial acetic acid is added dropwise over a twenty minute period at 45 maintaining the pH at 3 with sodium hydroxide. After heating for twenty minutes longer; the mixture is cooled and the NZN dimethyI- i-amino 9 methylpteroylglutamic acid filtered err; weight, 6.4 g. This compound has the follow ing formula:

N'Hz Example 15 g To a mixture of 5.32 g. of 2-dimethylamino, 4,5,6-triaminopyrimidine sulfate, 4.88 g. barium chloride, and 3.24 g. of para-methylaminobenzoyl glutamic acid disodium salt in 140 ml. of water at 45 C. and pH 3 are added dropwise solutions of 4.4 g. of 2,3dibromopropionaldehyde in 4 ml. of glacial acetic acid and 2.5 g. of iodine plus 5 of potassium iodide in 16 ml. of water over a twenty minute period. The pH is maintained at 3 with sodium hydroxide during this period. After heating thirty minutes longer, the pH is adjusted to 4., the mixture cooled, and the product, N ,N -dimethyl-4-amino-N methylpteroylglutamic acid, having the formula:

.. is filtered off; weight, 7.1 g.

Example 16 2 dimethylamino 4,5,6 triaminopyrimidine r: sulfate is reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylaspartic acid in the same manner as described in Example 13 to yield N ,N -dimethyli-aminopteroylaspartic acid'having the structural formula:

Example 18 2 dimethylamino 4,5,6 triaminopyrimidine sulfate is reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylglutamylglutamylglutamic acid in the same fashion as described in Example 13 to produce N ,N -dimethy1-4- aminopteroylglutamylglutamylglutamic acid.

Example 19 To a solution of 25.8 g. (0.21 mole) of 1,1-dimethylguanidine hydrochloride in 50 ml. of anhydrous methanol is added a solution of 22.7 g. (0.42 mole) of sodium methylate in 60 ml. of methanol. This mixture is heated to refluxing, and 20.7 g. (0.21 mole) of methyl cyanoacetate is added dropwise over a ten minute period. The

mixture is then refluxed for three hours, filtered from sodium chloride, and neutralized with hydrochloric acid. A white precipitate forms, which is filtered off after cooling; After drying, this Weighs 26.0 g., representing an 81% yield of 2-dimethylamino-4-hydroXy-6-amin0pyrimidine. After recrystallization from water the product melts at 290.5-292.5 C.

Two grams of Z-dimethylamino-4-hydroxy-6- aminopyrimidine is slurried in 20 ml. of water. warmed, and acidified until all is in solution. The pH is adjusted to 4 with sodium acetate, and 0.74 g. of sodium nitrite in 2 m1. of water added slowly at 80 C. A dark purple solution is formed which yields a red precipitate on cooling. This can be recrystallized from water, and the 2-dimethylamino 4 hydroxy 5 nitroso-G-amino pyrimidine melts with decomposition at 250 C.

Five grams of 2-dimethylamino-4-hydroxy-5- nitroso-6-aminopyrimidine is mixed with 30 ml. of water and sodium hydroxide added to dissolve it. Sodium dithionite is then added to this solution at 50 C. until the red color of the mixture has disappeared. This requires approximately 10 g. On cooling, a yellow precipitate is formed, which is isolated; dry weight, 3.5 g. The 2-dimethylamino-4-hydroxy-5,6 diaminopyrimidine sulfite is recrystallized from water in the presence of a trace of sodium dithionite and dried in vacuo.

A solution of g. of 2-dimethylamino-4-hydroxy-5,6-diaminopyrimidine sulfite in 330 ml. of water is adicified with hydrochloric acid, and the sulfur dioxide which is formed is removed by warming under vacuum. To the resultant solution is added 10.7 g. of para-aminobenzoylglutamic acid and the pH adjusted to 3.0 with sodium hydroxide. To this mixture at 45 C. are added dropwise and simultaneously solutions of 3.98 g. of sodium dichromate in 23 ml. of Water and 17.3 g. of 2,3-dibromopropionaldehyde in 16 ml. of glacial acetic acid over a twenty minute period. The pH is maintained at 3 during this period. After an additional 20 minutes at 45 C., the mixture is cooled to 10 C., and the product filtered off. This weighs approximately 21.3 g. and has a chemical assay of 24.8% as NN -dimethylpteroylglutamic acid. This is purified as follows: 20 g. is slurried in 1600 mlzof water, heated to 80 C., and 37 m1. of 5 N sodium hydroxide added. After fifteen minutes, a solution of 5.1 g. of calcium chloride in 14 ml. of solution is added. and

Iii!

12 the mixture is filtered with the aid of diatomaceous earth. The filtrate is acidified with 10% zinc chloride to pH 10.8 and filtered again. It is then neutralized to pH 3, cooled to 5 C., and filtered with the aid of diatomaceous earth. The cake is taken up in dilute alkali and reprecipitated at pH 3 again. The resultant cake is then slurried in 375 ml. of water with 4.5 g. of lime, heated at C. for 15 minutes and filtered. The filtrate is acidified with 10% zinc chloride to pH 10.8, filtered again, and the solution neutralized to pH 3 with hydrochloric acid, cooled, and the precipitate filtered off. The precipitate is mixed with 450 ml. of water and 0.25 g. of magnesium oxide added. After fifteen minutes at 60 C., 0.2 g. of activated charcoal is added. The mixture is clarified, and the product precipitated at pH 3 again. It is then recrystallized twice from volumes of 0.1 N hydrochloric acid, yielding a microcrystalline solid with a chemical assay of 85.1% as N ,N -dimethylpteroylglutamic acid with the following structural formula:

CH5 000 o H L w HOOC-CHrCH:

HHNJl-QNHCHr-K 3 Example 21 0 11000 0 i l \CH HAJHNHiQHNCH \N N JHa (B which can be named N ,N -dimethyl-9-methylpteroylglutamic acid, is filtered off; weight 3.8 g.

Example 22 A solution of 4.4 g. of 2-dimethylamino-4-hydroxy-5,G-diaminopyrimidine sulfite is converted to the hydrochloride with hydrochloric acid and the resultant sulfur dioxide removed under vacuum. To this solution is added 3.24 g. of para methylaminobenzoylglutamic acid disodium salt, and the pH adjusted to 3. The mixture is heated to 45 C., and solutions of 4.4 g. of 2,3-dibromopropionaldehyde in 4 ml. of glacial acetic acid and 2.5 g. of iodine plus 5 g. of potassium iodide in 16 ml. of water added dropwise over a twenty minute period, maintaining the pH at 3 by the addition of sodium hydroxide. The mixture is heated for thirty minutes longer, cooled, filtered after adding 1 g. of diatomaceous earth. The resultant N ,N -dimethylN -methy1pteroylglu tamic acid weighs 3.7 g., and has the structural formula:

3 with sodium hydroxide.

13 Example 23 I This reaction is carried out in the same fashion .asdescribed in Example 21, substituting 3.24 g. of para-methy1aminobenzoylglutamic acid disodium salt for, the para-aminobenzoylglutamic acid. The product, N ,N'--dimethy19.10-dimethylpteroylglutamic acid, has the following structural formula:

The product is isolated with the aid of 1. g. of diatomaceous earth and weighs 2.9 g. after drying.

Example 24 Example 25 2-dimethylamino-4-hydroxy 5,6 diaminopyrimidine sulfite is reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylglutamylglutamylglutamic acid in the same fashion as described in Example 20 to produce N ,N -dimethylpteroylglutamylglutamylglutamic acid.

Example 26 2-dimethylamino-4-hydroxy 5,6 diaminopy rimidine sulfiteis reacted with 2,3-dibromopropionaldehyde and para-aminobenzoylserylglu- HOOC O nn HOOC-CHrH:

tamic acid in the same manner as described in Example 20 to produce N ,N -dimethy1pteroyllutamic acid.

Example 27 Fifty grams of ZA-diamino-6-chloropyrimi dine, 92 g. of para-aminobenzoylglutamic acid and 1'70 ml. of dry ethylene glycol are heated together at 130 C. for three hours, cooled, and poured into several volumes of water. The resultant clear solution is rendered alkaline to benzoazurine test paper and warmed on the steam bath for fifteen minutes. Sodium hydroxide is added as needed to retain the alkalinity. The mixture is then clarified and added to a dilute acetic acid solution, causing the separation of a gummy precipitate which solidifies on washing with water. This is reprecipitated from alkaline medium, yielding a solid product, para-(2,4- diamino 6 p-yrimidyl) aminobenzoylglutamic acid, which is dried under reduced pressure, yielding a brittle solid which can be ground to a fine powder; weight 82.2 g.

To a suspension of 71 g. of para-(2,4-diamino- G-pyrimidyl) -aminobenzoylglutamic acid in 1400 ml. of water are added '70 ml. of N hydrochloric acid and 70 m1. of glacial acetic acid. The mixture is warmed until complete solution is obtained, and the pH adjusted to approximately A concentrated so.- dium nitrite solution is then added dropwise to l t N HNC Hrthe above mixture at C. until a permanent.

spot on starch-potassium iodide paper is reached. Just one mole of sodium nitrite is taken up. An orange-red precipitate of para- (ZA-diamino--nitroso 6 -pyrimidyl) aminobenzoylglutamic acid is obtained, which is isolated and used as such in the next reaction.

The product of the above reaction is mixed with 1400 ml. of water and sodium hydroxide added until complete solution is obtained.-- The mixture is then heated to 45 C. and sodium dithionite added until the red color of the solution is gone. Approximately g. is required. The product is then slowly addedrto dilute sulfuric acid, making sure to keep the mixture acid to Congo red at all times. A light yellow precipitate I of para(2:,4,5-triamino-6-pyri-midyl)- aminobenzoylglutamic acid sulfate is obtained which after isolation and drying weighs 70 g.

A mixture of 10 g. of para-(2,4,5-triamino-6- pyrimidyl)aminobenzoylglutamic acid sulfate and 4.93 g. of barium chloride in 250 ml. of water is heated on the steam bath for ten minutes and filtered from barium sulfate. Then 2.7 g. of paraaminobenzoylglutamic acidis added and the pH adjusted to 2.5 with sodium hydroxide. To this mixture at 45 C. is then added dropwise a solution of 4.36 g. of 2,3-dibromopropionaldehyde in 4 ml. of glacial acetic acid and 1.01 g. of so dium dichromate in 12. ml. of water over a twenty minute period. The pH is maintained between 2.5 and 3 with sodium hydroxide. After thirty minutes longer at 45 C., the mixture is cooled and the precipitate filtered off, washed with water and acetone and dried. The para- [N,N'-(2- amino 6 methylpteridyl 4,9) -bis-amino]ben zoylglutamic acid weighs 9.6 g., and has the structural formula-t in which R is a member of the group consisting of hydroxyl and amino acid radicals; R is a member of the group consisting of amino, lower monoalkylamlno and 'lower dialkylamino radicals; R, is a member'of the group consisting of amino, hydroxyl, lower monoalkylamino, lower dialkylamino, phenylamino and l-piperidyl radicals, at least one of the groups R and B being a substitutedlamino radical and Y is a member or the group consisting of hydrogen and lower alkyl radicals.

8. Compounds of the group consisting of those in which R is a lower dialkylamino radical and NHR is the radical of an amino acid.

9. A method which comprises mixing together under reactive conditions a pyrimidine having the formula:

having the general formula:

HzN

in which R is a member of the group consisting of amino, lower monoalkylamino and lower dialkylamino radicals and R is a member of the group consisting of amino, hydroxyl, lower monoalkylamino, lower dialkylamino, phenylamino and l-piperidyl radicals, at least one of the group R and R being a substituted amino radical, an aldehyde having the formula:

H Hal Hal o=t H x in which Hal is a member of the group consisting of chlorine and bromine atoms, X is amemher of the group consisting of hydrogen and halogen radicals and Y is a member of the group consisting of hydrogen and lower alkyl radicals and a member of the group consisting of an aminobenzoic acid, a lower alkylaminobenzoic acid and amino acid amides thereof and after reaction thereof, recovering a compound having the formula:

l l N Y Y in which R R and Y are as defined above and R is a member of the group consisting of hydroxyl and amino acid radicals.

10. A method which comprises mixing together in a solvent at a temperature within the range of about 0 C. to about 100 C. a 2,4,5-triamino- 6-l0wer dialkylaminopyrimidine, a 2,3-dihalopropionaldehyde and an amino acid amide 'of para-aminobenzoic acid and after reaction there of, recovering a compound having the formula:

in which R is a lower dialkylamino radical and NHR is a radical of an amino acid.

BARBARA ROTH.

No references cited. 

7. COMPOUNDS OF THE GROUP CONSISTING OF THOSE HAVING THE GENERAL FORMULA:
 9. A METHOD WHICH COMPRISES MIXING TOGETHER UNDER REACTIVE CONDITIONS A PYRIMIDINE HAVING THE FORMULA: 